package com.imooc.o2o.util;

import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class DESUtils {

	private static Key key;
//	设置密钥key
	private static String KEY_STR = "myKey";
	private static String CHARSETNAME = "UTF-8";
	private static String ALGORITHM = "DES";

	static {
		try {
//			生成DES算法对象
			KeyGenerator generator = KeyGenerator.getInstance(ALGORITHM);
//			运用SHA1安全策略
			SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
//			设置上密钥种子
			secureRandom.setSeed(KEY_STR.getBytes());
//			初始化基于SHA1的算法对象
			generator.init(secureRandom);
//			生成密钥对象
			key = generator.generateKey();
			generator = null;
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	public static String getEncryptString(String str) {
//		基于base64编码,接收byte[]并转换成String
		BASE64Encoder base64encoder = new BASE64Encoder();
		try {
//			按utf8编码
			byte[] bytes = str.getBytes(CHARSETNAME);
//			获取加密对象
			Cipher cipher = Cipher.getInstance(ALGORITHM);
//			初始化密码信息
			cipher.init(Cipher.ENCRYPT_MODE, key);
//			加密
			byte[] doFinal = cipher.doFinal(bytes);
//			byte[] to encode好的String并返回
			return base64encoder.encode(doFinal);
		} catch (Exception e) {
			// TODO: handle exception
			throw new RuntimeException(e);
		}
	}

	/**
	 * 获取解密之后的信息
	 * @param str
	 * @return
	 */
	public static String getDecryptString(String str) {
//		基于base64编码,接收byte[]并转换成String
		BASE64Decoder base64decoder = new BASE64Decoder();
		try {
//			将字符串decode成byte[]
			byte[] bytes = base64decoder.decodeBuffer(str);
//			获取解密对象
			Cipher cipher = Cipher.getInstance(ALGORITHM);
//			初始化解密信息
			cipher.init(Cipher.DECRYPT_MODE, key);
//			解密
			byte[] doFinal = cipher.doFinal(bytes);
//			返回解密之后的信息
			return new String(doFinal, CHARSETNAME);
		} catch (Exception e) {
			// TODO: handle exception
			throw new RuntimeException(e);
		}
	}
	
	public static void main(String[] args) {
		System.out.println(getEncryptString("root"));
		System.out.println(getEncryptString("230230"));
		System.out.println(getEncryptString("wxd7f6c5b8899fba83"));
		System.out.println(getEncryptString("665ae80dba31fc91ab6191e7da4d676d"));
	}

}